Firearm system with fire mode selector switch

ABSTRACT

Implementations of the present invention relate to apparatuses, systems, and methods for firing a belt-fed closed-bolt firearm by delivering an impulse from an impulse source along a first axis to a firing pin on a second axis. The first axis and second axis are not coaxial, allowing the impulse source to be disposed away from and not in direct contact or alignment with the firing pin.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. Non-Provisionalapplication Ser. No. 15/268,374 filed Sep. 16, 2016 entitled FIRINGBLOCK ASSEMBLY, which is incorporated herein by reference and which is acontinuation of U.S. Non-Provisional application Ser. No. 14/585,969filed Dec. 30, 2014 entitled “INTEGRATED SLIDE-CARRIER AND FIRING BLOCKASSEMBLY” which is incorporated herein by reference, and which claimspriority to and the benefit of U.S. Provisional Patent Application No.61/926,029, filed Jan. 10, 2014, titled “INTEGRATED SLIDE-CARRIER ANDFIRING BLOCK ASSEMBLY,” which is incorporated herein by reference. Eachof the foregoing applications is incorporated herein by reference.

BACKGROUND OF THE DISCLOSURE 1. The Field of the Invention

Generally, this disclosure relates to firearms. More specifically, thepresent disclosure relates to methods, devices, and systems foroperating a closed-bolt belt-fed firearm with greater reliability ofoperation, flexibility in platform, and ease of maintenance.

2. Background and Relevant Art

Belt-fed machine guns generally fall into two broad categories based onthe way the gun fires ammunition: open-bolt or closed-bolt. In anopen-bolt gun, the operating group, which includes the bolt, is heldtoward the rear of the receiver and away from chamber when not firing.The operating group is restrained, under tension from a spring, suchthat when the operating group is released, it moves forward forcefully.The forward movement shears a bullet off of a belt, delivers the bulletto the chamber, closed the chamber, and fires the bullet. In aclosed-bolt gun, the operating group is held forward and against thebarrel extension when not firing. The bolt is mated and locked to thebarrel extension forming a closed chamber. The chamber may house abullet waiting to be fired by an impulse from a hammer or other impulsesource delivered to the bullet's primer by a firing pin.

An open-bolt gun is inherently a machine gun. Without input from anoperator, an open-bolt gun will continuously fire, typically at a veryhigh rate, as long as the weapon has ammunition or until the gunmalfunctions. Each time the operating group moves forward in anopen-bolt gun, the forward motion detonates the bullet's primer, firingthe gun. The firing of a bullet generates a rapidly expanding gas withinthe barrel and some of the gas is diverted to a gas piston which forcesthe operating group rearward, opening the chamber and moving the nextround into position, before a spring forces the operating group forwardagain, repeating the process until the ammunition is exhausted or anoperator restrains the operating group in a rearward position.

A closed-bolt gun, conversely, may remain at rest with the operatinggroup forward and a bullet chambered. The firing pin remains withdrawnfrom the bullet until an impulse source, such as a hammer or a striker,delivers an impulse to the firing pin to detonate the primer and chargein the bullet. At which time, the expanding gas in the barrel may bediverted to provide energy to cycle the operating group similarly to anopen-bolt gun, except when the spring returns the operating group to aforward position, the bolt locks adjacent the barrel extension and thebullet in the chamber awaits the operator releasing the impulse source.

Prior to the Firearms Owners' Protection Act of 1986, open-bolt machineguns could be newly registered legally in the United States. TheFABRIQUE NATIONALE D'HERSTAL (“FN”) MINIMI open-bolt machine gun (andthe affiliated United States variant, the M249 light machine gunplatform) was among the most common open-bolt machine guns available atthe time, and remains one of the most common open-bolt machine guns inthe world. The FN MINIMI was originally developed in 1974 and hascontinued in operation with militaries in 45 countries. There are agreat deal of parts, accessories, and assemblies available for theplatform on the market, and the transfer of open-bolt machine gunslegally registered before May 19, 1986 is legal through proper channelsand with proper documentation. However, the production of new open-boltmachine guns, such as the M249 platform, for civilian sale in the UnitedStates is now illegal. Due to the reputation and restricted availabilityof the M249 platform, there remains a demand for M249-type firearmsamong civilians, as well as a robust market around the original guns.

However, an open-bolt belt-fed machine gun, such as the M249 platformhas a number of disadvantages for use in military or law enforcementconflicts despite the high rate of fire of the weapon. Typically, thehigh rate of fire of the M249 platform (approximately 800 rounds perminute) results in challenges for the operator to control the recoil andtherefore accuracy of the weapon. Furthermore, in many cases, theadvantages of outputting up to 800 rounds per minute may be outweighedby the consumption of ammunition. For example, 200 rounds of 5.56 mm×45mm NATO ammunition, not including the belt links, weighs almost 6 poundsand an M249-platform machine gun can fire all 6 pounds of ammunition in15 seconds. The M249 platform also supports a 7.62 mm×51 mm NATO variantthat weighs twice as much per round. Therefore, mobility of the gun andoperator is directly tied to ammunition consumption.

Closed-bolt rifles are legal to manufacture, sell, and own (whenproperly registered in territories required registration) and are notsubject to many of the 1986 registration limitations. Closed-bolt riflescapable of full-automatic firing are still regulated. Conversion of asemiautomatic closed-bolt gun to a full-automatic closed-bolt gun ispossible with a registered sear that is properly registered withappropriate authorities. However, closed-bolt rifles are capable ofsemi-automatic fire, burst fire (a fixed number of rounds greater thanone), or full-automatic fire with each pull of the trigger. Furthermore,the different firing modes of closed-bolt rifles may be freely selectedby a fire mode selector switch commonly mounted on the grip of the rifleallowing a closed-bolt rifle to be freely altered betweensemi-automatic, burst, and full-automatic firing modes quickly andeasily depending on the needs of the operator.

The closed-bolt, hammer- or striker-operated platform, therefore, hasoperational flexibility that an open-bolt platform cannot offer.Additionally, there are many manufacturers that offer a wide variety ofhammer- or striker-operated trigger packages for sale. For example,HECKLER & KOCH manufactures hammer-operated trigger packages that offerselectable fire modes between “safe;” semi-automatic fire; burst fire oftwo, three, or more rounds at a time; or full-automatic and anycombination thereof.

However, an open-bolt gun is not hammer- or striker-operated, andtherefore, there is no mechanism by which a hammer or striker may strikea firing pin. Previous attempts to simply drill a bore through the slideand extend the firing pin through the operating group necessitated anadditional extension of a hammer beyond the available sizes as isdescribed in “MGA's Semiautomatic MK46 Variant” by Dan Shea, The SmallArms Review, Vol. 13 No. 4, January 2010, pp. 48-54, which isincorporated herein in its entirety by reference. The target operationallifetime for belt-fed firearms is more than 100,000 rounds. The extralength of the bore, firing pin, and hammer all create additional strainon internal components resulting in increased likelihood of firearmfailure.

Therefore, it would be desirable to enable the use of a hammer- orstriker-operated trigger package with selectable fire modes with anM249-type platform by conversion of the open-bolt M249 or similarplatform to a closed-bolt platform and providing a mechanism by which acommercially available standard hammer or striker may impart force to afiring pin.

BRIEF SUMMARY OF THE DISCLOSURE

Implementations of the present disclosure solve one or more of theforegoing or other problems in the art with apparatuses, systems, andmethods for detonating a round in a closed-bolt self-loading firearmusing a non-coaxial impulse source. The present disclosure provides anintegrated slide-carrier and firing block, which function to couple theimpulse source, such as a hammer or striker, to the firing pin where themotion of the impulse source and the firing pin are not coaxial.

Additional features and advantages of exemplary implementations of theinvention will be set forth in the description which follows, and inpart will be obvious from the description, or may be learned by thepractice of such exemplary implementations. The features and advantagesof such implementations may be realized and obtained by means of theinstruments and combinations particularly pointed out in the appendedclaims. These and other features will become more fully apparent fromthe following description and appended claims, or may be learned by thepractice of such exemplary implementations as set forth hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to describe the manner in which the above-recited and otheradvantages and features of the invention can be obtained, a moreparticular description of the invention briefly described above will berendered by reference to specific embodiments thereof which areillustrated in the appended drawings. For better understanding, the likeelements have been designated by like reference numbers throughout thevarious accompanying figures. Understanding that these drawings depictonly typical embodiments of the invention and are not therefore to beconsidered to be limiting of its scope, the invention will be describedand explained with additional specificity and detail through the use ofthe accompanying drawings in which:

FIG. 1 depicts an isometric exploded view of a firearm according to thepresent disclosure;

FIG. 2 depicts a lower isometric exploded view of the firearm of FIG. 1;

FIG. 3 depicts an isometric view of an integrated slide-carrieraccording to the present disclosure;

FIG. 4 depicts a left side view of the integrated slide-carrier of FIG.3;

FIG. 5 depicts a left side cross-sectional view of the integratedslide-carrier of FIG. 3;

FIG. 6 depicts a left side cross-sectional view of the integratedslide-carrier of FIG. 3, further including a firing pin and firingblock;

FIG. 7 depicts a rear end view of the integrated slide-carrier andfiring block of FIG. 6;

FIG. 8 depicts a front end view of the integrated slide-carrier of FIG.3;

FIG. 9 depicts an isometric view of the firing block of FIG. 6;

FIGS. 10A-C depict a left side view of the rotation of a bolt due tolinear movement of the integrated slide-carrier of FIG. 3;

FIGS. 11A-C depict a left side cross-sectional view of the rotation of abolt due to linear movement of the integrated slide-carrier of FIG. 3;

FIGS. 12A-B depict a left side cross-sectional view the detonation of abullet by transmitting an impulse through the firing block of FIG. 6;

FIGS. 13A-C depict a left side cross-sectional view of resetting ahammer due to the linear movement of the integrated slide-carrier ofFIG. 3;

FIGS. 14A-C depict the use of a selector stop with a fire mode selectorswitch; and

FIG. 15 depicts an exploded view of the removable trigger package andselector switch.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

One or more implementations of the present invention relate to methods,devices, and systems for firing a closed-bolt self-loading firearm. Themethods, devices, and systems involve the transmission of force from animpulse source through a non-linear path to a propellant configured toaccelerate a projectile. The methods, devices, and systems may alsoallow the operation of other functionality of the firearm, such asfeeding ammunition, ejecting ammunition, resetting the impulse source oropening and closing a chamber.

The FABRIQUE NATIONALE D′HERSTAL (“FN”) M249 platform is one of the mostcommon light machine gun platforms in the world, including many variantsand having countless available accessories. However, the M249 platformis an open-bolt, slam fire weapon. The open-bolt, slam fire M249platform has only two modes of operation: 800 round-per-minute (“RPM”)fully automatic firing and not firing. When firing at 800 RPM, thefirearm is difficult to control and expends ammunition quickly. Anoption to operate the M249 platform as a closed-bolt, hammer firedweapon is desirable. However, the design of a closed-bolt, hammer firedgun on the M249 platform requires modification of the internal operatinggroup.

The present disclosure relates to the modification and replacement ofthe internal operating group to produce a closed-bolt, hammer firedoperation in an M249-type platform. The carrier, slide, recoil spring,gas tube, trunnion, gas block, grip, trigger housing, and operating rodmust all be redesigned; and a sear and trigger of the open-bolt systemmust be replaced with trigger package containing a hammer or otherimpulse source. A closed-bolt operating group may include an integrateslide-carrier that enables the use of a substantially standard bolt,firing pin, and trigger package, while translating the force appliedfrom a first axis to a second axis in order to allow proper operation ofthe firearm in a semi-automatic, burst-fire, or fully-automatic firingmode. The first and second axes may each be longitudinal axis and,therefore, parallel or non-parallel axes, such as perpendicular or at anacute angle to one another. Furthermore, the directions of the forces,even when the axes are parallel, may not be the same.

The integrated slide-carrier may incorporate the functionality of aslide and carrier while allowing additional functionality by removingthe division and, hence, connection therebetween. The slide-carrier mayallow for more reliable operation of the gun with less moving parts toreplace or maintain and for less chance of failure in the field. Theslide-carrier may also allow the transmission of a firing force from animpulse source through the slide-carrier to a firing pin, which may thentransmit the force to a propellant in the ammunition. The slide-carriermay also enable the translation of the firing force in a non-linear pathor along more than one axis.

The elimination of the connection between the slide and carrier mayenable the integrated slide-carrier to transmit force from expanding gasrod to the slide more directly. The monolithic construction of theintegrated slide-carrier may thereby reduce torque applied on receiverrails to which the slide-carrier is slidably mounted. Reduced torque onthe slide may reduce wear on the receiver rails, providing a furtherincrease in reliability and reduction in maintenance of the firearm.

FIG. 1 depicts an isometric exploded view of the main operationalcomponents of an embodiment of a firearm 100 including an integratedslide-carrier assembly. FIG. 2 depicts a lower isometric exploded viewof the main components of the firearm 100. The firearm 100 includes areceiver 200, which may carry upon it various information engraved orotherwise affixed thereto. The information on the receiver 200 maycommonly include model designation and identification information uniqueto that receiver to identify the firearm 100 for registration andownership purposes. The receiver 200 may also enable the connection andassembly of many of the operational components on or in the receiver200. For example, the receiver 200 includes a receiver body 202 thatdefines an interior channel 204 with left and right receiver rails 206a, 206 b affixed thereto. The left receiver rail 206 a and rightreceiver rail 206 b may be symmetrical with respect to one another, orthey may be asymmetrical. For example, the left receiver rail 206 a andthe right receiver rail 206 b may have differing thicknesses or they maybe positioned differently in the interior channel 204. The left receiverrail 206 a may be thicker or thinner than the right receiver rail 206 b.Additionally or alternatively, the left receiver rail 206 a may bepositioned higher or lower than the right receiver rail 206 b.Furthermore, the left receiver rail 206 a may be longer or shorterlongitudinally within the interior channel 204 than the right receiverrail 206 b. The receiver 200 further comprises a selector stop 210. Theselector stop 210 may be affixed to an exterior surface of the receiveror may be a raised portion of the receiver itself. The selector stop 210inhibits a fire mode selector switch 512 such as that found oncommercially available hammer-operated trigger packages from reaching a“disassemble” position, as will be explain in relation to FIGS. 14A-C.

The operating group 300 is slidably connected to the receiver 200 by theleft and right receiver rails 206 a, 206 b. The operating group 300includes the integrated slide-carrier 302 (described further in FIGS.3-8) having an elongate upper section in which there are left and rightlongitudinal recessions 304 a, 304 b. The left and right longitudinalrecessions 304 a, 304 b receive the left and right receiver rails 206 a,206 b, respectively, to allow the longitudinal movement of the operatinggroup 300 within the interior channel 204 of the receiver 200. Theoperating group 300 further includes a firing block 306 that is disposedat least partially inside the integrated slide-carrier 302.Alternatively, the firing block 306 may be disposed entirely externallyto the integrated slide-carrier. (The firing block 306 will also bedescribed more fully in relation to FIGS. 5-9.) The firing block 306transmits a force to the firing pin assembly 308, which is at leastpartially disposed within a bolt 310. The bolt 310 includes notches,grooves, channels, or threads for selectively connecting to another,complementary connector.

Still referring to FIG. 1, the receiver 200 also includes a centraltrunnion 208 into which the barrel assembly 400 connects. The barrelassembly 400 comprises a barrel body 402 that includes a bore 404therethrough. The bore 404 provides communication between the barrelbody 402 and a barrel extension 406. Together, the barrel extension 406and the bore 404 provide a path through which a bullet (not shown) mayexit the firearm 100.

The barrel assembly 400 also includes a gas block 408 disposed on thebarrel body 402 forward of the barrel extension 406. The gas block 408covers a gas port 410 and provides fluid communication with a gas blockoutlet 412. After firing a bullet, rapidly expanding gas may travel thelength of the barrel body 402 through the bore 404. As the gas passesthe gas port 410, the gas block 408 may channel some of the gaslaterally away from the bore 404 and toward the gas block outlet 412.The diverted gas may be expelled through the gas block outlet 412 andprovide the motive force to cycle the firearm 100 and prepare for asubsequent firing.

The barrel assembly 400 connects to the receiver 200 by inserting thebarrel extension 406 into the central trunnion 208. The barrel extension406 may connect to the trunnion 208 via threads, a twist lock, afriction fit, a weld, an adhesive or other secure attachment. Theconnection between the barrel 406 and the trunnion 208 may beselectively attachable to facilitate maintenance and repair of thefirearm 100. The barrel extension 406 provides complementary notches,grooves, channels, or threads into which the bolt 310 may be receivedand selectively secured thereto. The connection of the bolt 310 to thebarrel extension 406 provides a selectively securable connection betweenthe barrel assembly 400 and the internal operating group 300. Theconnection of the operating group 300 and the barrel assembly 400provides a chamber in which a bullet may be held and fired (visible inFIGS. 12A-B).

Still referring to FIG. 1, the firearm 100 further includes a controlassembly 500 disposed on the underside of the firearm 100 andselectively connected to the receiver 200. The control assembly includesa housing 502 with front mounting points 504 and rear mounting points506. The front mounting points 504 may be a notch that is configured tobe received into a recession on the receiver body 202, eyelets for across-bar, a snap fit, or other similar selectively securableconnection. Similarly, the rear mounting points 506 may be a notchconfigured to be received into a recession on the receiver body 202,eyelets for a cross-bar, a snap fit, or other similar selectivelysecurable connection. A trigger package 508 is disposed within thehousing 502 of the control assembly 500. The trigger package includes animpulse source such as a hammer 510, as depicted in FIG. 1, or a strikeror other similar linear actuator. The trigger package 508 may be acommercially available trigger package and may include safe,semi-automatic, 2-round burst, 3-round burst, fully automatic, or otherfire operation modes selectable with a fire mode selector switch 512.The trigger package 508, more specifically, may comprise a HECKLER ANDKOCH trigger package. The trigger package 508 may operate the firearm100 without modification to the trigger mechanism. Other modificationsnot affecting the trigger mechanism may include, for example, removal ofthe ejector.

Continuing to refer to FIG. 1, the firearm 100 further comprises a gaspiston assembly 600 that provides a fluid and mechanical linkage betweenthe barrel assembly 400 and the operating group 300. The gas pistonassembly 600 connects the barrel assembly 400 to the operating group 300by a gas piston-and-cylinder linkage. The gas tube 602 is disposedaround, or otherwise forms a fluid seal with, the gas block outlet 412.The gas block outlet 412 may provide a source of high pressure gas,which may impinge upon a surface of a gas piston 604. The gas piston 604is connected to a rigid operating rod 606, which is, in turn, connectedto the operating group 300. The operating rod 606 is connected to theoperating rod connection 312 on the integrated slide-carrier 302 of theoperating group 300. The connection between the operating rod 606 andthe operating rod connection 312, and the connection between the gaspiston 604 and the operating rod 606, may be any connection ofsufficient strength to communicate the compressive and tensile forcesproduced during operation of the firearm 100. For example, theconnection may be threads, a twist lock, a friction fit, a weld, anadhesive or other secure attachment. Preferably the connection may be aselective connection facilitating maintenance and repair of the firearm100, and more preferably, the connection may be adjustable to allowprecise tuning of the operation of the firearm 100. For example, theconnection may be a threaded connection providing a selective andadjustable connection. A threaded connection may further comprise alateral set screw to retain the connection at the selected relativeposition.

The gas piston assembly 600 may allow the high pressure gas, the gascontained within the barrel bore 404 and directed through the gas block408 and gas port 410 to the gas block outlet 412, to provide the energyfor a motive force to cycle the operating group 300. The motive forcemay be a reciprocal linear force resulting from the pressure of theimpinging gas from the gas block outlet 412 in the rearward direction,and an opposite linear force from a recoil spring 608 disposedcircumferentially around the operating rod and compressed between asurface of the gas piston 604 and a bushing 610 disposed adjacent thetrunnion 208. The bushing 610 is an annular bushing configured to allowthe operating rod 606 to slide through a central opening in the bushing610 while the recoil spring 608 is retained by an annular surface of thebushing 610. Hence, when the high pressure gas impinges upon the gaspiston 604, the gas piston 604 travels rearward along the length of thegas tube 602, and compresses the recoil spring 608 against the bushing610 adjacent the trunnion 208. The seal between the gas piston 604 andthe gas tube 602 allows for the passage of a portion of the highpressure gas, allowing dissipation of the pressure in the gas tube 602.The gas that escapes beyond the gas piston 604 may then pass throughchannels in the bushing 610 and escape the firearm 100, dissipating thegas in the gas tube 602.

The recoil spring 608 may then provide a restoring force in oppositionto the rearward movement of the gas piston 604. The restoring forcecauses the gas piston 604 to travel forward in the gas tube 602 untilthe gas piston 604 returns to a position adjacent the gas block outlet412. Thus, each firing of the firearm 100 may result in a reciprocalmotion of the gas piston 604 within the gas tube 602. The reciprocalmotion of the gas piston 604 within the gas tube 602 with each firing ofthe firearm 100 provides the motive force to reciprocally move theoperating group 300 within the receiver 200.

The reciprocal motion of the operating group 300 may provide the inputforce for nearly all other operations of the firearm 100, as will bediscussed in relation to FIGS. 10-15. For example, the motion of theoperating group 300 after the firing of a first round and theintroduction of high-pressure gas through the gas port 610 and into thegas tube 602, unlocks the bolt 310 from the barrel extension 406,extracts a shell casing, ejects the shell casing, resets the triggerpackage 508, removes a second round from an ammunition source, insertsthe second round into the barrel extension 406, and then locks the bolt310 in the barrel extension 406. Many of these functions are provided bythe integrated slide-carrier 302 of the operating group 300, depicted indetail in FIGS. 3-8.

As can also be seen in FIG. 1, the firearm 100 comprises a top cover700, as is known in the art, configured to feed in a belt of ammunition.The top cover 700 feeds ammunition with a lever-activated feed driven bythe bearing 328 of the operating group 300. The bearing 328 may follow atrack in the top cover 700 providing an incremental, lateral feed ofammunition, as is visible in FIG. 2. The top cover 700 is specific tothe type and size of ammunition being fired.

Referring now to FIG. 3, the integrated slide-carrier 302 comprises theleft and right longitudinal recessions 304 a, 304 b, which receive theleft and right receiver rails 206 a, 206 b respectively to facilitatethe longitudinal, reciprocal movement of the operating group 300 withinthe interior channel 204 of the receiver 200. The integratedslide-carrier 302 also comprises a slide bore 314, into which a firingpin 308 and bolt 310 (not depicted) may be inserted. The bore extendsfrom near a forward end of the integrated slide-carrier 302substantially through the length of the integrated slide-carrier 302,but not through the entire integrated slide-carrier 302. The bore isrecessed from a front end of the integrated slide-carrier 302 to allowthe bolt 310 (not depicted) to properly lock into the barrel extension406.

Referring now to FIG. 4, the front end of the integrated slide-carrier302 comprises an upper front surface 316 a and a lower front surface 316b, which are co-planar. The co-planar upper front surface 316 a andlower front surface 316 b extend on either side of the barrel extension406 when the firearm 100 is in battery. The integrated slide-carrier 302is held against the barrel extension 406 by the recoil spring 608 andthe operating rod 606 connected to the operating rod connector 312. Acontact surface 316 c may distribute the compressive force between theintegrated slide-carrier 302 and the barrel extension 406 to reducestrain and wear on the integrated slide carrier 302.

Still referring to FIG. 4, the integrated slide-carrier 302 furthercomprises a rotation channel 318 associated with the slide bore 314. Therotation channel 318 guides the rotation of the bolt 310 to lock andunlock the bolt 310 from the complementary channels in the barrelextension 406. The rotation channel 318 comprises an upper portion 318a, a catch 318 b, a rotational portion 318 c, and a longitudinal portion318 d. The upper portion 318 a has a rearward slanted front face and avertical rear face, while the rotational portion 318 c has a forwardslanted front face and forward slanted rear face, while the catch 318 bforms the junction of the upper portion 318 a and the rotational portion318 c. The upper portion 318 a allows manual removal or installation ofa bolt 310 by rotating the bolt 310 through the upper portion 318 a anddrawing the bolt 310 out through the slide bore 314. During normaloperation, however, the catch 318 b prevents the unintended removal ofthe bolt 310.

Still referring to FIG. 4, the integrate slide-carrier 302 comprises alower support 320. The lower support 320 provides structural support tothe integrated slide-carrier 302 and thereby reduces strain and wear onthe integrated slide-carrier 302 to prevent failure of the operatinggroup 300. The lower support 320 extends substantially the length of theintegrated slide-carrier 302 and defines a central space 322. The lowersupport 320 connects to the remainder of the integrated slide-carrier302 by one or more points. The central space 322 is devoid of materialor may comprise material of different mass than the integratedslide-carrier 302, in order to tune the mass of the operating group 300.The mass of the operating group 300 may need to change to ensure properoperation of the firearm 100 depending on operating conditions,ammunition type, the spring constant of the recoil spring 608, the sizeof the gas port 410, or other factors.

The integrated slide-carrier 302 additionally comprises a sear releasearm 324, enabling the firearm 100 to be operated in a fully automaticfiring mode. The sear release arm 324 is configured to release a sear ina hammer-operated fully automatic firing mechanism, such as some HECKLERAND KOCH trigger packages. The integrated slide-carrier 302 alsocomprises a bevel 326 configured to engage a hammer 510 or other impulsesource of a trigger package 508 and reset the hammer 510 or otherimpulse source as the operating group 300 cycles rearward after firing.The integrated slide-carrier 302 may also comprise a channel configuredto hold the bearing 328 which may engage with a top cover 700 (notdepicted) to feed ammunition automatically into the firearm 100.

As shown in FIG. 5, the slide bore 314 extends through some, but not allof the integrated slide-carrier 302. Alternatively, the slide bore 314may extend through substantially the entire length of the integratedslide-carrier 302. The slide bore 314 includes a hole for a borecross-pin 330 that intersects the slide bore 314 and may retain thefiring pin 308 within the slide bore 314. The bore cross-pin 330 retainsthe firing pin 308 within a desired range of motion, allowing for theselective extension of the firing pin 308 through and out of the bolt310 to set off the ammunition when in battery.

The integrated slide-carrier 302 includes a rear channel 334, whichcommunicates with the slide bore 314 in a rear portion of the slide bore314. The rear channel 334 of the integrated slide-carrier 302 includesrear channel rails 336 recessed into the sides of the rear channel 334.The rear channel rails 336 extend forward from a rear surface of theintegrated slide-carrier 302 and may be symmetrical on opposing faces ofthe rear channel 334. As can be seen in FIG. 6-8, the firing block 306is disposed at least partially within the rear channel 334, at leastpartially within the slide bore 314, and at least partially outside ofthe integrated slide-carrier 302. Alternatively, the firing block 306may be disposed externally to the integrated slide-carrier 302.

As shown in FIG. 7, the firing block 306 is disposed between thesubstantially opposing lateral faces of the rear channel 334 andsubstantially fills a lateral width of the rear channel 334. The widthof the firing block 306 is such that the firing block 306 cannot turnlaterally and jam within the rear channel 334. The firing block 306comprises firing block rails 338 that align with the rear channel rails336 disposed in the lateral faces of the rear channel 334. The rearchannel rails 336 and the firing block rails 338 may be identical butmirrored versions of one another, but need not be. For example, the rearchannel rails 336 and the firing block rails 338 of FIG. 7 are bothsemi-circular in transverse cross-section, but in other embodiments maybe triangular in transverse cross-section, or may be rectangular intransverse cross-section. Alternatively, the rear channel rails 336 maybe semi-circular in transverse cross-section, triangular in transversecross-section, or rectangular in transverse cross-section, and thefiring block rails 338 may have a different cross-section.

In any configuration, the rear channel rails 336 and the firing blockrails 338 may form a cavity in which a guide pin 340 (shown in dashedlines in FIG. 7) may be disposed. FIG. 7 depicts an integratedslide-carrier 302 and firing block 306 with two pairs of rear channelrails 336 and firing block rails 338 providing two cavities in which twoguide pins 340 are disposed. The guide pins 340 retain the firing block306 along a longitudinal path of travel and restrict the longitudinalrotation of the firing block 306 such that the firing block does not jamin the rear channel 334 or the slide bore 314 during longitudinalmovement. The guide pins 340 are retained by a rail cross-pin 332 thatinhibits rearward movement of the guide pins 340.

As shown in FIG. 8, the rear channel 334 intersects with the slide bore314, but the slide bore 314 and the rear channel 334 only partiallyoverlap due to the slide bore 314 extending only part of the length ofthe integrated slide-carrier 302 and not extending all the way to therear of the integrated slide-carrier 302. The firing block 306 is,therefore inserted into the rearward portion of the slide bore 314 andthen held within a predetermined range of positions by the guide pins340.

FIG. 9 depicts the firing block 306 that is disposed at least partiallywithin the rear channel 334, at least partially within the slide bore314, and at least partially outside of the integrated slide-carrier 302.The firing block 306 transfers energy from a hammer 510 or other impulsesource in a trigger package 508 on a first axis to a firing pin 308 on alongitudinal second axis. The first axis is also longitudinal, but neednot be in alternative embodiments. Similarly, the second axis isparallel to the first axis, but need not be in alternative embodiments.The firing block 306 is generally L-shaped, but in other embodiments,the firing block may be triangular, rectangular, or any other shapecapable of transferring mechanical forces from a first axis to a second,parallel axis. The firing block 306 comprises a firing pin contactsurface 342 and a hammer contact surface 344. The firing pin contactsurface 342 is configured to deliver an impulse to the firing pin 308reliably, and therefore includes a flat surface to be disposed incontact with, or adjacent to a rearward end of the firing pin 308. Thefiring pin contact surface 342 protrudes forward into the slide bore 314and beyond the rear channel 334. The firing pin contact surface 342protruding beyond the rear channel 334 allows the firing pin contactsurface 342 to contact the rear end of the firing pin 308 withoutneeding the rear end of the firing pin 308 to extend past the forwardend of the rear channel 334. If the firing pin 308 extends too farrearward, the firing pin 308 may catch on the forward end of the rearchannel 334 and could lead to the firearm 100 jamming during operation.

The hammer contact surface 344 disposed is at the rear of the firingblock 306 and extends beyond the rear end of the integratedslide-carrier 302 such that a hammer or other impulse source from thetrigger package 504 may contact the hammer contact surface 344. Thehammer contact surface 344 is configured to receive an impulse from thetrigger package 508 reliably, and therefore includes a flat surface tobe disposed in contact with, or adjacent to, a hammer 510 or otherimpulse source of the trigger package 508. Additionally, to withstandthe receipt of and to properly transmit tens or hundreds of thousands ofimpulses from the trigger package 508, the firing block 306 isreinforced in some areas and lightened in other areas. For example, thefiring block 306 may have additional material in a flared portion 346leading to the hammer contact surface 344. The additional material inthe flared portion 346 toughens the firing block 306 in that region andenhances the operational lifetime of the firing block 306.

Furthermore, the firing block 306 comprises a brace 348 that extendsdiagonally from the corner of the generally L-shaped firing block 306.The brace 348 aids in transmitting the impulse from the trigger package508 to the firing pin 308 sufficiently efficiently to allow the removalof material elsewhere, such as a void 350, without degrading theperformance of the firing block 306. By removing material and having avoid 350 in the firing block 306, the overall mass and therefore inertiaof firing block 306 may be reduced, resulting in a more immediatetransfer of energy from the trigger package 508 to the firing pin 308.Also, a firing block 306 of greater mass and inertia may be more likelyto prematurely firing the firearm 100 when the operating group 300cycles forward. To ensure the firing block 306 remains within thedesired range of movement, a pin slot 352 is included near the hammercontact surface 344 through which the rail cross-pin 332 is disposed,restricting movement of the firing block 306 and ensuring the firingblock does not fall out of the integrated slide-carrier 302.

Referring now to FIG. 10A-C, the catch 318 b retains the bolt 310 andurges the bolt 310 rearward during rearward motion of the integratedslide-carrier 302 and assists in aligning the bolt head 310 a with thebarrel extension 406 (barrel extension 406 not depicted in FIGS. 10A-C).Upon forward motion of the operating group 300 toward the barrelextension 406, the bolt 310 contacts the barrel extension 406 first andthe integrated slide-carrier 302 continues moving forward, compressing afiring pin spring 354 and pushing the bolt 310 into the slide bore 314.The firing pin spring 354 is at least partially recessed into an annularrecession in the bolt 310 to prevent kinking of the firing pin spring354 during compression.

As shown in FIG. 10B, as the bolt 310 moves into the slide bore 314, therotational portion 318 c rotates the bolt 310 by applying torque to thebolt guide member 310 b. The bolt guide member 310 b slides along therotational portion 318 c as the slide-carrier 302 moves forward. Therotation of the bolt head 310 a locks the bolt 310 relative to thebarrel extension 406, providing a sealed chamber in which to fire abullet. The integrated slide-carrier 302 then continues moving towardthe barrel extension 406 while the bolt remains stationary and locked,as shown in FIG. 10C. The integrated slide-carrier 302 continues movingtoward the barrel extension because the bolt 310 should be fully rotatedand locked relative to the barrel extension 406 before the firing pin308 (visible in FIG. 11A-C) is positioned adjacent the bullet.

FIGS. 11A-C depict the same process in a cross-section view to show thecompression of the firing pin spring 354 and the movement of theintegrated slide-carrier 302 and firing pin 308 relative to the bolt310. The catch 318 b retains the bolt 310 and urges the bolt 310rearward during rearward motion of the integrated slide-carrier 302 andassists in aligning the bolt head 310 a with the barrel extension 406(barrel extension 406 not depicted in FIGS. 11A-C). Upon forward motionof the operating group 300 toward the barrel extension 406, the bolt 310contacts the barrel extension 406 first and the integrated slide-carrier302 continues moving forward, compressing a firing pin spring 354 andpushing the bolt 310 into the slide bore 314.

As shown in FIG. 11B, as the bolt 310 moves into the slide bore 314, therotational portion 318 c rotates the bolt 310 by applying torque to thebolt guide member 310 b. The bolt guide member 310 b slides along therotational portion 318 c as the slide-carrier 302 moves forward. Therotation of the bolt head 310 a locks the bolt 310 relative to thebarrel extension 406, providing a sealed chamber in which to fire abullet. The integrated slide-carrier 302 continues moving toward thebarrel extension 406 while the bolt remains stationary and locked, asshown in FIG. 11C. The integrated slide-carrier 302 continues movingtoward the barrel extension because the bolt 310 should be fully rotatedand locked relative to the barrel extension 406 before the firing pin308 is positioned adjacent the bullet.

As can be seen in FIG. 11, the firing pin spring 354 applies a force tothe bolt 310 and the firing pin 308 that urges the two apart. Becausethe bolt 310 is locked relative to the barrel extension 406, the firingpin spring 354 urges the firing pin 308 away from the bolt 310 andrearward in the slide bore 314. However, the rearward travel of thefiring pin 308 is limited by a bore cross-pin 330 and/or by the firingblock 306, itself. The firing pin 108 is urged away from the bolt head310 a and, therefore, away from the bullet B held in the chamber. Thefiring pin 308 has a degree of travel around the bore cross-pin 330,however, which may be less than about 2 mm, less than about 1.5 mm, orless than about 1 mm. The force applied by the firing pin spring 354 tourge the firing pin 308 away from the bolt 310 and rearward in the bore314 may also urge the firing block 306 rearward. As the firing block 306moves rearward within the rear channel 334, at least part of the firingblock 306 protrudes from the integrated slide-carrier 302 or otherwisebe configured to receive an impulse from a trigger package 508. Theprotruding portion of the firing block 306 includes the hammer contactsurface 344.

As shown in FIGS. 12A-B, once in battery, the operating group 300 isready to transmit an impulse from the trigger package 508 to a bullet B.The hammer contact surface 344 protrudes from the rear channel 334 andthe firing pin contact surface 342 may be in contact with or adjacent tothe firing pin 308. The firing pin 308 rests on the bore cross-pin 330and is held there by a force applied between the bolt 310 and the firingpin 308 by the firing pin spring 354. As depicted in FIG. 12A, whenresting on the bore cross-pin 330 due to a rearward force applied by thefiring pin spring 354, a tapered end of the firing pin 308 a may besubstantially flush with a surface of the bolt head 310 a or may berecessed therefrom. The tapered end of the firing pin 308 a may,therefore, by adjacent or proximate a bullet B.

FIG. 12B shows a movement of the firing pin 308 in response to animpulse provided by a trigger package 508. The impulse may be providedby a hammer 510 moving in a substantially arcuate fashion, as shown inFIG. 12B, a striker moving in a substantially linear fashion, or anyother mechanical impulse source configured to trigger an impact orimpulse to an explosive such as the primer in a bullet B. In anembodiment, the impulse is delivered by a curved hammer 510, such asthat depicted in FIGS. 12A-B. In a further embodiment, the impulse maybe delivered by a HECKLER AND KOCH hammer operated trigger package. In ayet further embodiment, the impulse may be delivered by a HECKLER ANDKOCH hammer operated trigger package that is substantially unmodified.In a still yet further embodiment, the impulse may be delivered by aHECKLER AND KOCH hammer operated trigger package that is modified onlyto remove the ejector from the trigger package. In an embodiment, thefirearm 100 is a HECKLER AND KOCH host.

The impulse is received by a hammer contact surface 344 of the firingblock 306 and transmitted by the firing block 306 to a firing pin 308through a firing pin contact surface 342 of the firing block 306. Uponreceiving the impulse, the firing block 306 slides forward on the guidepins 340, moving substantially coaxially to the application of theimpulse. The impulse source from the trigger package 508 may remain incontact with the firing block 306 while the firing block 306 contactsthe firing pin 308, or the impulse source may strike the firing blockand, after imparting energy to the firing block 306, retract from thefiring block 306. In an embodiment, the impulse source from the triggerpackage 508 applies a force to the firing block 306 and continuesapplying a force to the firing block 306 even after the firing block 306travels forward and pushes the firing pin 308 forward.

FIG. 13A shows the operating group 300 and the trigger package 508 inthe short time immediately following the combustion of the propellant inthe bullet B. After the trigger package 508 has provided an impulse tothe operating group 300, and, particularly, the hammer contact surface344 of the firing block 306, to fire a bullet B, the expanding gas willimpinge upon the gas piston 604 (not depicted in FIGS. 13A-C) and applya rearward force on the operating rod 606, which is coupled to theoperating rod connection 312 of the integrated slide-carrier 302. Theforce drives the operating group 300 rearward on the receiver rails 206a, 206 b (not depicted) and the resulting rearward motion of theintegrated slide-carrier applies a rearward force to the impulse sourceof the trigger package 508. For example, the impulse source may be ahammer 510, as depicted in FIG. 13A, but may also be a striker or otherlinear impulse source. When the integrated slide-carrier 302 movesrearward relative to the trigger package 508, the hammer 510 will bealso urged rearward. The hammer 510 moves within a substantially arcuatepath, and therefore, moving the hammer 510 rearward will cause thehammer 510 to also move toward the trigger package 508 and out of therearward path of the operating group 300.

As shown in FIG. 13B, a bevel 326 disposed on a portion of theintegrated slide-carrier 302 nearest the hammer 510 aids in directingthe hammer 510 out of the path of the integrated slide-carrier 302 andtoward the trigger package 508 and housing 502. In an alternativeembodiment, the bevel 326 may alternatively be a rounded corner of theintegrated slide-carrier 302 such that the rounded corner also providesa gradual and lower friction application of force to the hammer 510 orother impulse source in order to reset the hammer 510 or other impulsesource, as depicted in FIG. 13C, with an increased efficiency versus anintegrated slide-carrier 302 with a squared corner. The lower support320 holds the hammer 510 or other impulse source in its reset positionfor substantially the entire motion of the operating group 300 duringthe cycling of the firearm 100 in order to give the trigger package 508as much time as is available to safely reset the trigger and preventadditional automatic firing, be it a single round or a “runaway”firearm, or to prevent the hammer 510 merely following the operatinggroup 300 forward and failing to impart a sufficient impulse to detonatea primer. When in fully automatic firing mode, the sear catch arm 324engages a sear on an appropriate fully automatic trigger package 508 andallows for a delayed release of the hammer 510 or other impulse source.The delayed release of the hammer 510 or other impulse source ensuresthe impulse is sufficient to detonate a primer.

Referring now to FIGS. 14A-C, the fire mode selector switch 512 ismounted on the housing 502 and trigger package 508, and selects the firemode for the trigger package 508. While a three-position fire modeselector switch 512 is depicted in FIGS. 14A-C, a number of triggerpackages 508 are commercially available, including variants that mayinclude more than three positions. As shown in FIG. 13A, acounterclockwise-most position of the three-position fire mode selectorswitch 512 is a “disassemble” position. When the fire mode selectorswitch 512 is in the counterclockwise-most position, it may be removedfrom the housing 502 and from the trigger package 508. The fire modeselector switch 512 is the only connection that retains the triggerpackage 508 in the housing 502. Therefore, when the fire mode selectorswitch 512 is removed from the housing 502 and trigger package 508,there are no further connections holding the trigger package 508 inplace, and the trigger package 508 is free to move within the housing502 and within the receiver body 202.

As can be seen in FIG. 14B, to prevent accidental removal of the firemode selector switch 512 when the firearm 100 is assembled, a selectorstop 210 is disposed on the receiver body 202 such that the“disassemble” position may not be achieved when the control assembly 500is attached to the receiver 200. The fire mode selector switch 512 isdepicted in a second position in FIG. 14B. The second position issubstantially rotationally adjacent the selector stop 210. In anembodiment, the second position may be a “safe” mode, in which thetrigger package 508 is inhibited from releasing the hammer 510 or otherimpulse source and the firearm 100 is therefore unable to fire. Inanother embodiment, the second position may be a firing mode, and thefiring mode may include a semi-automatic, burst-fire, or fully-automaticfiring mode.

FIG. 14C depicts a third position of the fire mode selector switch 512,which is rotationally further from the selector stop 210 than the secondposition. In an embodiment, the third position may be a “safe” mode, inwhich the trigger package 508 is inhibited from releasing the hammer 510or other impulse source and the firearm 100 is therefore unable to fire.In another embodiment, the third position may be a firing mode, and thefiring mode may include a semi-automatic, burst-fire, or fully-automaticfiring mode.

FIG. 15 depicts an exploded view of the removable trigger package 508from the grip housing 502. Fire mode selector switch shaft 514 extendsthe width of the housing 502. When the trigger package 508 is disposedwithin the housing 502, housing port 516 aligns with trigger packageport 518, and fire mode selector switch shaft 514 may be insertedthrough the width of the housing 502 and the trigger package 508 tosecure the trigger package 508 within the housing 502.

When the fire mode selector switch 512 rotates to the “disassemble”position depicted in FIG. 14A, the fire mode selector switch 512 may beremoved. There is no other connection between the trigger package 508and the grip housing 502 securing the trigger package 508 in the griphousing 502. Therefore, upon removal of the fire mode selector switch512 (by lateral movement of the fire mode selector switch 512) from thegrip housing 502 and the trigger package 508, the trigger package 508 isno longer secured to any part of firearm 100.

The terms “approximately,” “about,” and “substantially” as used hereinrepresent an amount close to the stated amount that still performs adesired function or achieves a desired result. For example, the terms“approximately,” “about,” and “substantially” may refer to an amountthat is within less than 10% of, within less than 5% of, within lessthan 1% of, within less than 0.1% of, and within less than 0.01% of astated amount.

The present invention may be embodied in other specific forms withoutdeparting from its spirit or essential characteristics. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive. The scope of the invention is, therefore, indicatedby the appended claims rather than by the foregoing description. Allchanges that come within the meaning and range of equivalency of theclaims are to be embraced within their scope.

1. A system comprising: an elongate receiver defining an interior volumeand having an exterior surface; a trigger package having a rotatablefire mode selector switch, the fire mode selector switch being disposedproximate the exterior surface; and a selector stop disposed on theexterior surface and configured to partially inhibit rotation of thefire mode selector switch.
 2. The system of claim 1, wherein therotatable fire mode selector is removable from the trigger pack whenrotated to a disassemble position.
 3. The system of claim 2, wherein theselector stop is configured to inhibit the fire mode selector switchfrom achieving the disassemble position.
 4. The system of claim 1,wherein the selector stop is affixed to the exterior surface of thereceiver.
 5. The system of claim 1, wherein the selector stop is araised portion of the exterior surface of the receiver.
 6. The system ofclaim 1, further comprising a housing in which the trigger package isdisposed, wherein the trigger package is connected to the housing byonly the fire mode selector switch.